upgraded ecu codes??

[SpeedFreak_Josh]

Does anybody know if the upgraded ecu's cannot monitor all the same systems as when stock?I have a miss in my Z but no light. Thanks

btw> It's from Stillen
Modified by SpeedFreak_Josh at 3:17 PM 5/21/2007

[evildky]

I believe the remapped ecu simply changed the mapping, and just becasue you have no light doesn't eman you don't have a code, you might want to find someone with a consult to plug in and see what they find

[Remmik]

http://www.ttzd.com/tech/diagnostictech.html Check this link out. This is a simple enough diagnostic anyone can do. It's pretty easy if you read carefully. I think only about 12 of the 18 faults make the EngineLight flash. Keep in mind that there is allot more..ALLOT more that the CPU can't monitor that would make your engine run poorly or not at all. As far as the "Upgraded ECU's", they only install a chip that has new parameters that govern the engine but all monitoring is done the same. Also, new parameters can greatly effect old parts on your engine by causing more stress. Like your spark plugs can foul real quick if they were already in bad shape. You should also list as much as possible as far as what your Z has as far as upgrades and the exact circumstance and frequency of your problem. Always go overkill on info you post, you never know what info might be of great use in diagnosing your problem..

[SpeedFreak_Josh]

OK, here goes. I have a 1990 300zx tt 5spd. I purchase it last summer from an older man who had it 6 months and bought it from the original owner who lived in Cali. The car has stage III all from Stillen. Also, lightweight flywheel and stage 3 ACT clutch, short shifter & turbo timer(HKS). Everything was purchased by the orig owner. I spoke to him about maintainance and he mentioned every once in a while the car would start and miss. He said he would rev it once or twice and it would go away. When I bought the car it had no problems. I changed the oil and cleaned the intake cone(stillen) with K&N cleaner. It ran fine for about a month. Then the check engine light came on once in 2nd gear @about 5-10 mph cruising through a subdivision. It went off after about 10 seconds. Did the same thing again under similar scenario about 2-3 weeks later but the light stayed on for about 15-20 minutes, then went out- all while driving. Both times i didn't notice any difference in the car's performance. After a couple more weeks, I started getting a miss/hesitation while cruising most noticeable in fourth and fifth around 2-2500rpm. <No check engine light, and none since. The miss is only noticeable while cruising under light throttle. I changed the plugs. No difference. The car has always been garage kept and all wiring/hosing is in very good condition. To be sure I checked the PTU. It's the new style and all wiring is like new. The coil packs all looked good too.I've printed out the ECU code check and am going to check it later this week since I'll be gone this weekend.I originally thought spark, but now I'm not so sure. I've gone through more gas so it's not that.I've gone to school for automotive but don't have much experience on the Z.Any help from the experienced would be greatly appreciated.

[SpeedFreak_Josh]

Update:I ran the self diagnostic test. Got code 55 = no error codes. 02s checked ok.sprayed the MAF with electrical contact cleaner. Ran a little sea foam through an intake vacuum line. Little to no change. Still have the miss but I didn't get to drive too much. Bout 10 min. The miss is almost like a jolt. I can make it happen by going on/off on the throttle. I've also noticed that there is a slight lope while idling. I can't remember if it's new or not though.